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MICHELE BIANCHI

Ricercatore t.d. art. 24 c. 3 lett. B
Dipartimento di Scienze della Vita sede ex Chimica V.Campi 103

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Pubblicazioni

2023 - Electrospun fibers coated with nanostructured biomimetic hydroxyapatite: A new platform for regeneration at the bone interfaces [Articolo su rivista]
Di Pompo, Gemma; Liguori, Anna; Carlini, Martina; Avnet, Sofia; Boi, Marco; Baldini, Nicola; Focarete, Maria Letizia; Bianchi, Michele; Gualandi, Chiara; Graziani, Gabriela
abstract

: Reconstruction of gradient organic/inorganic tissues is a challenging task in orthopaedics. Indeed, to mimic tissue characteristics and stimulate bone regeneration at the interface, it is necessary to reproduce both the mineral and organic components of the tissue ECM, as well as the micro/nano-fibrous morphology. To address this goal, we propose here novel biomimetic patches obtained by the combination of electrospinning and nanostructured bone apatite. In particular, we deposited apatite on the electrospun fibers by Ionized Jet Deposition, a plasma-assisted technique that allows conformal deposition and the preservation in the coating of the target's stoichiometry. The damage to the substrate and fibrous morphology is a polymer-dependent aspect, that can be avoided by properly selecting the substrate composition and deposition parameters. In fact, all the tested polymers (poly(l-lactide), poly(D,l-lactide-co-glycolide, poly(ε-caprolactone), collagen) were effectively coated, and the morphological and thermal characterization revealed that poly(ε-caprolactone) suffered the least damage. The coating of collagen fibers, on the other hand, destroyed the fiber morphology and it could only be performed when collagen is blended with a more resistant synthetic polymer in the nanofibers. Due to the biomimetic composition and multiscale morphology from micro to nano, the poly(ε-caprolactone)-collagen biomimetic patches coated with bone apatite supported MSCs adhesion, patch colonization and early differentiation, while allowing optimal viability. The biomimetic coating allowed better scaffold colonization, promoting cell spreading on the fibers.

2023 - Nanoscale Quantized Oscillations in Thin-Film Growth Greatly Enhance Transconductance in Organic Transistors [Articolo su rivista]
Drakopoulou, S; Murgia, M; Albonetti, C; Benaglia, S; Borgatti, F; Di Lauro, M; Bianchi, M; Greco, P; Papo, D; Garcia, R; Alessandrini, A; Biscarini, F
abstract

A growth mode of pentacene thin films deposited by high vacuum sublimation where the morphology versus thickness h "rings" back and forth between rough 3D films with pyramid islands and smooth 2D films with ziqqurat islands is discovered. The roughness & sigma; versus h exhibits seamless coherent oscillations whose amplitude and wavelength increase as integer multiples of 1.5 ML thickness. The quantized oscillations are reconducted to dynamic wetting/dewetting transitions involving the upper layers of pentacene film. Importantly, the transconductance of organic field effect transistors, either in solid state or electrolyte-gated, exhibits antiphase oscillations with one-decade swing. Charge mobilities in the wetting regime reach 0.1 cm(2) V-1 s(-1), in line with high-end values reported for thin-film pentacene transistors. Controlling this growth mode enables the limitations of charge transport imposed by the roughening transition to be overcome, a universal feature of high vacuum growth to date.

2022 - A Novel Biasing Scheme of Electrolyte-Gated Organic Transistors for Safe In Vivo Amplification of Electrophysiological Signals [Articolo su rivista]
Di Lauro, M.; Zucchini, E.; De Salvo, A.; Delfino, E.; Bianchi, M.; Murgia, M.; Carli, S.; Biscarini, F.; Fadiga, L.
abstract

Successful translation of organic transistors as sensors and transducers to clinical settings is hampered by safety and stability issues. The operation of such devices demands driving voltages across the biotic/abiotic interface, which may result in undesired electrochemical reactions that may harm both the patient and the device. In this study, a novel operational mode is presented for electrolyte-gated organic transistors that avoid these drawbacks: the common-drain/grounded-source configuration. This approach reverts the standard common-source/common-ground configuration and achieves maximum signal amplification while applying null net bias across the electrolyte, with no parasitic currents. The viability of the proposed configuration is demonstrated by recording in vivo the somatosensory evoked activity from the barrel cortex of rats. The main inherent advantage of transistors with respect to passive electrodes is preserved in the proposed scheme: a superior signal-to-noise ratio is achieved which enables the detection of evoked activity at the single-trial level. Then, common-drain/grounded-source organic transistors are proposed as ideal candidate devices for a harmless translational recording platform.

2022 - Flexible Neural Interfaces Based on 3D PEDOT:PSS Micropillar Arrays [Articolo su rivista]
Lunghi, A.; Mariano, A.; Bianchi, M.; Dinger, N. B.; Murgia, M.; Rondanina, E.; Toma, A.; Greco, P.; Di Lauro, M.; Santoro, F.; Fadiga, L.; Biscarini, F.
abstract

Multi-electrode arrays with 3D micropillars allow the recording of electrophysiological signals in vitro with higher precision and signal-to-noise ratio than planar arrays. This is the result of the tight interaction between the 3D electrode and the cell membrane. Most 3D electrodes are manufactured on rigid substrates and their integration on flexible substrates is largely unexplored. Here, a straightforward approach is presented for fabricating soft interfaces featuring 3D poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) micropillars on a soft flexible substrate made of polydimethylsiloxane (PDMS). Large-area isotropic arrays of PEDOT:PSS micropillars with tailored geometric area, surface properties, and electrochemical characteristics are fabricated via a combination of soft-lithography and electrodeposition. A 60% increase in capacitance is achieved for high density micropillars compared to planar electrodes and this is found to be correlated with the increased electroactive surface area. Furthermore, 3D PEDOT:PSS micropillars support adhesion, growth and differentiation of SH-SY5Y cells, and influence the direction of neurite outgrowth. Finally, by virtue of their elasticity, soft micropillars act as excellent anchoring loci for elongating neurites, facilitating their bending and twisting around the micropillar, increasing the number of contact points between the cells and the electrode, a key requirement to obtain high performance neural interfaces.

2022 - Innovative Nanomaterials for Biomedical Applications [Articolo su rivista]
Bianchi, M.; Carnevale, G.
abstract

Research focusing on innovative nanomaterials for applications in biomedicine and bioengineering has steadily gained attention over the last 20 years [...].

2022 - Multifunctionally-doped PEDOT for organic electrochemical transistors [Articolo su rivista]
Carli, S; Bianchi, M; Di Lauro, M; Prato, M; Toma, A; Leoncini, M; De Salvo, A; Murgia, M; Fadiga, L; Biscarini, F
abstract

Organic Electrochemical Transistors (OECTs) are suitable for developing ultra-sensitive bioelectronic sensors. In the organic electrochemical transistors architecture, the source-drain channel is made of a conductive polymer film either cast from a formulated dispersion or electrodeposited from a monomer solution. The commercial poly(3,4-ethylenedioxidethiophene)/poly(styrene sulfonate) (PEDOT:PSS) water dispersion is the workhorse of organic bioelectronics for its high conductance, low impact and ease of processability. In this study, a hybrid organic electrochemical transistors channel fabrication strategy is presented, where electrochemical deposition of a PEDOT/X (with X indicating the counterion) is performed on a dispersion-cast PEDOT:PSS film. Six different counterions where used: X = PSS, Nafion, Hyaluronate, Dextran sulfate, Dexamethasone phosphate and tauroursodeoxycholic acid, each potentially endowing organic electrochemical transistors with additional functions such as ion exchange and pharmacological activity upon release of X. The PEDOT/X-PEDOT:PSS bilayers were characterized by means of electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and focused ion beam tomography combined with scanning electron microscopy (FIB-SEM). In addition, their respective organic electrochemical transistorss were characterized and compared to PEDOT:PSS organic electrochemical transistors. Our results show that the hybrid bilayer strategy is viable to fabricate multifunctional organic electrochemical transistorss with biologically-relevant function, thereby retaining the outstanding figures of merit of commercial PEDOT:PSS.

2022 - PEDOT: PSS promotes neurogenic commitment of neural crest-derived stem cells [Articolo su rivista]
Pisciotta, A.; Lunghi, A.; Bertani, G.; Di Tinco, R.; Bertoni, L.; Orlandi, G.; Biscarini, F.; Bianchi, M.; Carnevale, G.
abstract

: Poly (3,4-ethylendioxythiophene) polystyrene sulphonate (PEDOT:PSS) is the workhorse of organic bioelectronics and is steadily gaining interest also in tissue engineering due to the opportunity to endow traditional biomaterials for scaffolds with conductive properties. Biomaterials capable of promoting neural stem cell differentiation by application of suitable electrical stimulation protocols are highly desirable in neural tissue engineering. In this study, we evaluated the adhesion, proliferation, maintenance of neural crest stemness markers and neurogenic commitment of neural crest-derived human dental pulp stem cells (hDPSCs) cultured on PEDOT:PSS nanostructured thin films deposited either by spin coating (SC-PEDOT) or by electropolymerization (ED-PEDOT). In addition, we evaluated the immunomodulatory properties of hDPSCs on PEDOT:PSS by investigating the expression and maintenance of the Fas ligand (FasL). We found that both SC-PEDOT and ED-PEDOT thin films supported hDPSCs adhesion and proliferation; however, the number of cells on the ED-PEDOT after 1 week of culture was significantly higher than that on SC-PEDOT. To be noted, both PEDOT:PSS films did not affect the stemness phenotype of hDPSCs, as indicated by the maintenance of the neural crest markers Nestin and SOX10. Interestingly, neurogenic induction was clearly promoted on ED-PEDOT, as indicated by the strong expression of MAP-2 and β -Tubulin-III as well as evident cytoskeletal reorganisation and appreciable morphology shift towards a neuronal-like shape. In addition, strong FasL expression was detected on both undifferentiated or undergoing neurogenic commitment hDPSCs, suggesting that ED-PEDOT supports the expression and maintenance of FasL under both expansion and differentiation conditions.

2022 - Poly(3,4-ethylenedioxythiophene)-Based Neural Interfaces for Recording and Stimulation: Fundamental Aspects and In Vivo Applications [Articolo su rivista]
Bianchi, M.; De Salvo, A.; Asplund, M.; Carli, S.; Di Lauro, M.; Schulze-Bonhage, A.; Stieglitz, T.; Fadiga, L.; Biscarini, F.
abstract

Next-generation neural interfaces for bidirectional communication with the central nervous system aim to achieve the intimate integration with the neural tissue with minimal neuroinflammatory response, high spatio-temporal resolution, very high sensitivity, and readout stability. The design and manufacturing of devices for low power/low noise neural recording and safe and energy-efficient stimulation that are, at the same time, conformable to the brain, with matched mechanical properties and biocompatibility, is a convergence area of research where neuroscientists, materials scientists, and nanotechnologists operate synergically. The biotic–abiotic neural interface, however, remains a formidable challenge that prompts for new materials platforms and innovation in device layouts. Conductive polymers (CP) are attractive materials to be interfaced with the neural tissue and to be used as sensing/stimulating electrodes because of their mixed ionic-electronic conductivity, their low contact impedance, high charge storage capacitance, chemical versatility, and biocompatibility. This manuscript reviews the state-of-the-art of poly(3,4-ethylenedioxythiophene)-based neural interfaces for extracellular recording and stimulation, focusing on those technological approaches that are successfully demonstrated in vivo. The aim is to highlight the most reliable and ready-for-clinical-use solutions, in terms of materials technology and recording performance, other than spot major limitations and identify future trends in this field.

2021 - Evaluation of the in vitro biocompatibility of PEDOT: Nafion coatings [Articolo su rivista]
Guzzo, Sonia; Carli, Stefano; Pavan, Barbara; Lunghi, Alice; Murgia, Mauro; Bianchi, Michele
abstract

Poly(3,4-ethylenedioxythiophene)-Nafion (PEDOT:Nafion) is emerging as a promising alternative to PEDOT-polystyrene sulfonate (PEDOT:PSS) in organic bioelectronics. However, the biocompatibility of PEDOT:Nafion has not been investigated to date, limiting its deployment toward in vivo applications such as neural recording and stimulation. In the present study, the in vitro cytotoxicity of PEDOT:Nafion coatings, obtained by a water-based PEDOT:Nafion formulation, was evaluated using a primary cell culture of rat fibroblasts. The surface of PEDOT:Nafion coating was characterized by Atomic Force Microscopy (AFM) and water contact angle measurements. Fibroblasts adhesion and morphology was investigated by scanning electron microscopy (SEM) and AFM measurements. Cell proliferation was assessed by fluorescence microscopy, while cell viability was quantified by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT), lactate dehydrogenase (LDH) and neutral red assays. The results showed that PEDOT:Nafion coatings obtained by the water dispersion were not cytotoxic, making the latter a reliable alternative to PEDOT:PSS dispersion, especially in terms of chronic in vivo applications.

2021 - Implantable Organic Artificial Synapses Exhibiting Crossover between Depressive and Facilitative Plasticity Response [Articolo su rivista]
Calandra Sebastianella, G.; Di Lauro, M.; Murgia, M.; Bianchi, M.; Carli, S.; Zoli, M.; Fadiga, L.; Biscarini, F.
abstract

Organic neuromorphic devices mimic signal processing features of biological synapses, with short-term plasticity, STP, modulated by the frequency of the input voltage pulses. Here, an artificial synapse, made of intracortical microelectrodes, is demonstrated that exhibits either depressive or facilitative STP. The crossover between the two STP regimes is controlled by the frequency of the input voltage. STP features are described with an equivalent circuit where an inductance component is introduced in parallel with the RC circuit associated with poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate (PEDOT/PSS)||electrolyte interface. The proposed RLC circuit explains the physical origin of the observed STP and its two timescales in terms of charge build up in PEDOT/PSS.

2020 - A Comprehensive microstructural and compositional characterization of allogenic and xenogenic bone: Application to bone grafts and nanostructured biomimetic coatings [Articolo su rivista]
Graziani, G.; Vivarelli, L.; Boi, M.; De Carolis, M.; Bianchi, M.; Sassoni, E.; Bignozzi, M. C.; Carnevale, G.; Marmi, F.; Maltarello, M. C.; Dallari, D.; Govoni, M.
abstract

Bone grafts and bone-based materials are widely used in orthopedic surgery. However, the selection of the bone type to be used is more focused on the biological properties of bone sources than physico-chemical ones. Moreover, although biogenic sources are increasingly used for deposition of biomimetic nanostructured coatings, the influence of specific precursors used on coating's morphology and composition has not yet been explored. Therefore, in order to fill this gap, we provided a detailed characterization of the properties of the mineral phase of the most used bone sources for allografts, xenografts and coating deposition protocols, not currently available. To this aim, several bone apatite precursors are compared in terms of composition and morphology. Significant differences are assessed for the magnesium content between female and male human donors, and in terms of Ca/P ratio, magnesium content and carbonate substitution between human bone and different animal bone sources. Prospectively, based on these data, bone from different sources can be used to obtain bone grafts having slightly different properties, depending on the clinical need. Likewise, the suitability of coating-based biomimetic films for specific clinical musculoskeletal application may depend on the type of apatite precursor used, being differently able to tune surface morphology and nanostructuration, as shown in the proof of concepts of thin film manufacturing here presented.

2020 - Nanodecoration of electrospun polymeric fibers with nanostructured silver coatings by ionized jet deposition for antibacterial tissues [Articolo su rivista]
Pagnotta, G.; Graziani, G.; Baldini, N.; Maso, A.; Focarete, M. L.; Berni, M.; Biscarini, F.; Bianchi, M.; Gualandi, C.
abstract

Silver-based nanomaterials are used as antibacterial agents in a number of applications, including wound dressing, where electrospun materials can effectively promote wound healing and tissue regeneration thanks to their biomimicry, flexibility and breathability. Incorporation of such nanomaterials in electrospun nonwovens is highly challenging if aiming at maximizing stability and antibacterial efficacy and minimizing silver detachment, without neglecting process straightforwardness and scalability. In this work nanostructured silver coatings were deposited by Ionized Jet Deposition (IJD) on Polylactic acid, a medical grade polyester-urethane and Polyamide 6,6 nanofibers. The resulting materials were thoroughly characterized to gain an in-depth view of coating morphology and substrate resistance to the low-temperature deposition process used. Morphology of silver coatings with well-cohesive grains having dimensions from a few tens to a few hundreds of nanometers was analyzed by SEM, TEM and AFM. TGA, DSC, FTIR and GPC showed that the polymers well withstand the deposition process with negligible effects on their properties, the only exception being the polylactic acid that resulted more susceptible to degradation. Finally, the efficacy against S. aureus and E. coli bacterial strains was demonstrated, indicating that electrospun fibers decorated with nanostructured silver by IJD represent a breakthrough solution in the field of antibacterial devices.

2020 - Photovoltage generation in enzymatic bio-hybrid architectures [Articolo su rivista]
Di Lauro, M.; Buscemi, G.; Bianchi, M.; de Salvo, A.; Berto, M.; Carli, S.; Farinola, G. M.; Fadiga, L.; Biscarini, F.; Trotta, M.
abstract

Most of the photochemical activity of bacterial photosynthetic apparatuses occurs in the reaction center, a transmembrane protein complex which converts photons into charge-separated states across the membrane with a quantum yield close to unity, fuelling the metabolism of the organism. Integrating the reaction center from the bacterium Rhodobacter sphaeroides onto electroactive surfaces, it is possible to technologically exploit the efficiency of this natural machinery to generate a photovoltage upon Near Infra-Red illumination, which can be used in electronic architectures working in the electrolytic environment such as electrolyte-gated organic transistors and bio-photonic power cells. Here, photovoltage generation in reaction center-based bio-hybrid architectures is investigated by means of chronopotentiometry, isolating the contribution of the functionalisation layers and defining novel surface functionalization strategies for photovoltage tuning.

2020 - Scaling of capacitance of PEDOT:PSS: Volume: Vs. area [Articolo su rivista]
Bianchi, M.; Carli, S.; Di Lauro, M.; Prato, M.; Murgia, M.; Fadiga, L.; Biscarini, F.
abstract

Poly(3,4-ethylentedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is one of the most studied materials for organic bioelectronics, supercapacitors and organic photovoltaics. Its low impedance is ascribed to the so-called volumetric capacitance, a property that phenomenologically correlates the capacitive coupling/charge storage in devices to the PEDOT:PSS volume/thickness. Here we investigate the correlation between the capacitance and the electroactive surface area (ESA) for large-volume spin-cast PEDOT:PSS electrodes. We measure the capacitance with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), and characterize the surface morphology by atomic force microscopy and X-ray photoelectron spectroscopy. Capacitance of PEDOT:PSS films scales with volume up to ∼5 × 106 μm3 but is saturated at larger volumes. This scaling behavior is paralleled by the scaling of the ESA, hence the ratio between the effective capacitance and ESA remains constant across the whole data set, thus showing that the specific areal capacitance is indeed the relevant material property of PEDOT:PSS. EIS data fit supports the experimental evidence obtained by CV, further revealing that the diffusion time constant is also saturated at high volumes. This supports the scenario where the effective capacitance relates to the ion accessible ESA, and shows that the saturation of the capacitance arises from a change of ion penetration from a diffusive (at small volumes) to a non-diffusive regime at large volumes.

2020 - The pulsed electron deposition technique for biomedical applications: A review [Articolo su rivista]
Liguori, A.; Gualandi, C.; Focarete, M. L.; Biscarini, F.; Bianchi, M.
abstract

The "pulsed electron deposition" (PED) technique, in which a solid target material is ablated by a fast, high-energy electron beam, was initially developed two decades ago for the deposition of thin films of metal oxides for photovoltaics, spintronics, memories, and superconductivity, and dielectric polymer layers. Recently, PED has been proposed for use in the biomedical field for the fabrication of hard and soft coatings. The first biomedical application was the deposition of low wear zirconium oxide coatings on the bearing components in total joint replacement. Since then, several works have reported the manufacturing and characterization of coatings of hydroxyapatite, calcium phosphate substituted (CaP), biogenic CaP, bioglass, and antibacterial coatings on both hard (metallic or ceramic) and soft (plastic or elastomeric) substrates. Due to the growing interest in PED, the current maturity of the technology and the low cost compared to other commonly used physical vapor deposition techniques, the purpose of this work was to review the principles of operation, the main applications, and the future perspectives of PED technology in medicine.

2020 - Tunable Short-Term Plasticity Response in Three-Terminal Organic Neuromorphic Devices [Articolo su rivista]
Di Lauro, M.; De Salvo, A.; Sebastianella, G. C.; Bianchi, M.; Carli, S.; Murgia, M.; Fadiga, L.; Biscarini, F.
abstract

Reversibly tunable short-term plasticity (STP) of the channel current in organic neuromorphic devices is demonstrated with a three-terminal architecture. Electrolyte-gated organic transistors - EGOTs - are driven with square voltage pulses at the drain electrodes, while the gate bias enables the modulation of the amplitude and characteristic time scale of the depressive STP spiking response up to 1 order of magnitude. The gate potential sets the baseline and the steady-state current, preluding multilevel memory writing. The fine-tuning of the STP response, which is not possible with two-electrode organic neuromorphic devices, is reversible and does not imply chemical modifications of the active layer.

2020 - Water-Based PEDOT:Nafion Dispersion for Organic Bioelectronics [Articolo su rivista]
Carli, S.; Di Lauro, M.; Bianchi, M.; Murgia, M.; De Salvo, A.; Prato, M.; Fadiga, L.; Biscarini, F.
abstract

The water dispersion of the conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) is one of the most used material precursors in organic electronics also thanks to its industrial production. There is a growing interest for conductive polymers that could be alternative surrogates or replace PEDOT:PSS in some applications. A recent study by our group compared electrodeposited PEDOT:Nafion vs PEDOT:PSS in the use for neural recordings. Here, we introduce an easy and reproducible synthetic protocol to prepare a water dispersion of PEDOT:Nafion. The conductivity of the pristine material is on the order of 2 S cm-1 and was improved up to ≈6 S cm-1 upon treatment with ethylene glycol. Faster ion transfer was assessed by electrochemical impedance spectroscopy (EIS), and, interestingly, an improved adhesion was observed for coatings of the new PEDOT:Nafion dispersion on glass substrates, even without the addition of the silane cross-linker needed for PEDOT:PSS. As proof of concept, we demonstrate the use of this novel water dispersion of PEDOT:Nafion in three different organic electronic device architectures, namely, an organic electrochemical transistor (OECT), a memristor, and an artificial synapse.

2019 - Cartilage mechanical tests: Evolution of current standards for cartilage repair and tissue engineering. A literature review [Articolo su rivista]
Marchiori, G.; Berni, M.; Boi, M.; Bianchi, M.; Filardo, G.
abstract

Background: Repair procedures and tissue engineering are solutions available in the clinical practice for the treatment of damaged articular cartilage. Regulatory bodies defined the requirements that any products, intended to regenerate cartilage, should have to be applied. In order to verify these requirements, the Food and Drug Administration (FDA, USA) and the International Standard Organization (ISO) indicated some Standard tests, which allow evaluating, in a reproducible way, the performances of scaffolds/treatments for cartilage tissue regeneration. Methods: A review of the literature about cartilage mechanical characterization found 394 studies, from 1970 to date. They were classified by material (simulated/animal/human cartilage) and method (theoretical/applied; static/dynamic; standard/non-standard study), and analyzed by nation and year of publication. Findings: While Standard methods for cartilage mechanical characterization still refer to studies developed in the eighties, expertise and interest on cartilage mechanics research are evolving continuously and internationally, with studies both in vitro – on human and animal tissues – and in silico, dealing with tissue function and modelling, using static and dynamic loading conditions. Interpretation: there is a consensus on the importance of mechanical characterization that should be considered to evaluate cartilage treatments. Still, relative Standards need to be updated to describe advanced constructs and procedures for cartilage regeneration in a more exhaustive way. The use of the more complex, fibre-reinforced biphasic model, instead of the standard simple biphasic model, to describe cartilage response to loading, and the standardisation of dynamic tests can represent a first step in this direction.

2019 - Design of a novel procedure for the optimization of the mechanical performances of 3D printed scaffolds for bone tissue engineering combining CAD, Taguchi method and FEA [Articolo su rivista]
Marchiori, G.; Berni, M.; Boi, M.; Petretta, M.; Grigolo, B.; Bellucci, D.; Cannillo, V.; Garavelli, C.; Bianchi, M.
abstract

In order to increase manufacturing and experimental efficiency, a certain degree of control over design performances before realization phase is recommended. In this context, this paper presents an integrated procedure to design 3D scaffolds for bone tissue engineering. The procedure required a combination of Computer Aided Design (CAD), Finite Element Analysis (FEA), and Design methodologies Of Experiments (DOE), firstly to understand the influence of the design parameters, and then to control them. Based on inputs from the literature and limitations imposed by the chosen manufacturing process (Precision Extrusion Deposition), 36 scaffold architectures have been drawn. The porosity of each scaffold has been calculated with CAD. Thereafter, a generic scaffold material was considered and its variable parameters were combined with the geometrical ones according to the Taguchi method, i.e. a DOE method. The compressive response of those principal combinations was simulated by FEA, and the influence of each design parameter on the scaffold compressive behaviour was clarified. Finally, a regression model was obtained correlating the scaffold's mechanical performances to its geometrical and material parameters. This model has been applied to a novel composite material made of polycaprolactone and innovative bioactive glass. By setting specific porosity (50%) and stiffness (0.05 GPa) suitable for trabecular bone substitutes, the model selected 4 of the 36 initial scaffold architectures. Only these 4 more promising geometries will be realized and physically tested for advanced indications on compressive strength and biocompatibility.

2019 - Electrodeposited PEDOT:Nafion Composite for Neural Recording and Stimulation [Articolo su rivista]
Carli, S.; Bianchi, M.; Zucchini, E.; Di Lauro, M.; Prato, M.; Murgia, M.; Fadiga, L.; Biscarini, F.
abstract

Microelectrode arrays are used for recording and stimulation in neurosciences both in vitro and in vivo. The electrodeposition of conductive polymers, such as poly(3,4-ethylene dioxythiophene) (PEDOT), is widely adopted to improve both the in vivo recording and the charge injection limit of metallic microelectrodes. The workhorse of conductive polymers in the neurosciences is PEDOT:PSS, where PSS represents polystyrene-sulfonate. In this paper, the counterion is the fluorinated polymer Nafion, so the composite PEDOT:Nafion is deposited onto a flexible neural microelectrode array. PEDOT:Nafion coated electrodes exhibit comparable in vivo recording capability to the reference PEDOT:PSS, providing a large signal-to-noise ratio in a murine animal model. Importantly, PEDOT:Nafion exhibits a minimized polarization during electrical stimulation, thereby resulting in an improved charge injection limit equal to 4.4 mC cm−2, almost 80% larger than the 2.5 mC cm−2 that is observed for PEDOT:PSS.

2019 - Fabrication and characterization of biomimetic hydroxyapatite thin films for bone implants by direct ablation of a biogenic source [Articolo su rivista]
Graziani, Gabriela; Berni, Matteo; Gambardella, Alessandro; De Carolis, Monica; Maltarello, Maria Cristina; Boi, Marco; Carnevale, Gianluca; Bianchi, Michele
abstract

Biomimetic bone apatite coatings were realized for the first time by the novel Ionized Jet Deposition technique. Bone coatings were deposited on titanium alloy substrates by pulsed electron ablation of deproteinized bovine bone shafts in order to resemble bone apatite as closely as possible. The composition, morphology and mechanical properties of the coatings were characterized by GI-XRD, FT-IR, SEM-EDS, AFM, contact angle measurements, micro-scratch and screw-insertion tests. Different post-treatment annealing conditions (from 350 °C to 425 °C) were investigated. Bone apatite coatings exhibited a nanostructured surface morphology and a composition closely resembling that of the deposition target (i.e. natural bone apatite), also regarding the presence of magnesium and sodium ions. Crystallinity and composition of the coatings were strongly influenced by annealing temperature and duration; in particular, upon annealing at 400 °C and above, a crystallinity similar to that of bone was achieved. Finally, adhesion to the titanium substrate and hydrophilicity were significantly enhanced upon annealing, all characteristics being known to have a strong positive impact on promoting host cells attachment, proliferation and differentiation.

2019 - Nano-mechanical investigation of engineered bone tissue and of the osteochondral interface [Articolo su rivista]
Boi, M.; Marchiori, G.; Berni, M.; Fini, M.; Russo, A.; Bianchi, M.
abstract

Nanoindentation has been emerging as a powerful tool for the investigation of the quality of bone tissue, as it allows to relate compositional/structural heterogeneity to mechanical variations at the micro- and nano-scale. To date, the investigation of nanomechanical properties of bone has been almost exclusively limited to healthy or pathologic tissues, while very few studies attempted to evaluate the mechanical properties of the tissue during the regeneration process. Here, we report the analysis by nanoindentation of the mechanical properties of healing tissue considering different animal models (rabbit and sheep), anatomical regions (condylar osteochondral interface and femoral trabecular bone), comparing pre-existent (i.e. native) and newly-formed (i.e. engineered) tissue according to different engineering approaches. In particular, we focused on bone tissue regenerated by means of nanostructured multi-layered biomimetic scaffolds or macroporous hydroxyapatite scaffolds implanted in critical-size bone defects. Our data confirm that nanoindentation represents an extremely useful tool to follow the degree of maturation of bone tissue during the healing process, for instance allowing the comparison of the efficacy of different regenerative approaches. In addition, the knowledge of the level of reconstruction of the osteochondral interface by revealing the (nano-)mechanical gradient can provide clinically relevant information to predict the correct load transfer from the cartilage to the underlying bone tissue.

2019 - Nanoindentation: An advanced procedure to investigate osteochondral engineered tissues [Articolo su rivista]
Boi, Marco; Marchiori, Gregorio; Berni, Matteo; Gambardella, Alessandro; Salamanna, Francesca; Visani, Andrea; Bianchi, Michele; Fini, Milena; Filardo, Giuseppe
abstract

Osteochondral scaffolds are emerging as a promising alternative for articular cartilage regeneration, although with still controversial results. In particular, the restoration of the osteochondral interface remains an open challenge. The current available investigative procedures are not optimal to quantify the properties of this region, neither to evaluate the quality of the regenerated tissue with respect to the physiological one. This study investigates an advanced procedure able to quantitatively evaluate the mechanical gradient between stiff and compliant tissues, such as in the osteochondral region where the interface between hyaline and calcified cartilage (tidemark) plays an integral role in transferring articular loads from the compliant articular surface to the stiffer underlying bone. A series of nanoindentation line scans was performed along the tidemark - starting from hyaline and expanding across calcified cartilage - on histological sections derived from sheep osteochondral tissue regenerated by a three-layered biomimetic scaffold, as well as to the adjacent healthy tissue for comparative purposes. After an accurate assessment of the indentation parameters, a sigmoid curve-fit function was applied on the reduced modulus profiles to extract gap, width and regularity of the mechanical transition. The designed procedure succeeded in quantitatively assessing the transition between compliant and stiff regions, limiting experimental issues that generally affect the reliability of the indentation mechanical data, such as apex-blunt indenter tip effect, surface roughness, and influence of the substrate. Among the evaluated parameters, the mechanical gap highlighted the main difference between native and regenerated tissues. Thanks to the information retrievable through this procedure, this load transmission area can be further investigated, providing data to tailor osteochondral engineered tissues in the future.

2019 - Nanostructured Ag thin films deposited by pulsed electron ablation [Articolo su rivista]
Gambardella, A.; Berni, M.; Graziani, G.; Kovtun, A.; Liscio, A.; Russo, A.; Visani, A.; Bianchi, M.
abstract

Nanostructured thin films of silver (Ag) are receiving attention in many production fields requiring adaptation to different substrate materials and fine control over surface texture, such as hi-tech industry and biomedicine. Here we report the deposition at room temperature of Ag thin films by pulsed electron ablation, the films thickness ranging from tens to hundreds of nanometers. Films micro- and nanostructure were investigated by means of AFM, STM and XRD, and chemical composition assessed by XPS. The data were elaborated and discussed in the context of depositions under non-local growth effects, and compared with pulsed electron ablation of different target materials. Our films resulted nanometrically smooth and homogeneous, with high degree of purity and characterized by a narrow distribution of grains of nanometric size at all the thicknesses considered. We suggest that a balance between the efficiency of the ablation process and the unique properties of Ag as a metal accounts for the overall reduction of the system size, and is at the origin of the observed nanostructuration. Our results are interesting in the perspective of metals ablation and provide an optimal platform for the study of functional surfaces with high surface-to-volume ratio.

2018 - A comparative study of the growth dynamics of zirconia thin films deposited by ionized jet deposition onto different substrates [Articolo su rivista]
Gambardella, A.; Berni, M.; Russo, A.; Bianchi, M.
abstract

The use of ceramic coatings to improve mechanical, chemical, and biological properties of a large variety of materials including polymers and metals has often produced technologically attractive as well as problematic surfaces to study, because of their complicate morphology compared to smooth surfaces obtained, for example, by atomistic processes. In this work we deposited thin films of zirconia by a new generation pulsed electron deposition system named Ionized Jet Deposition onto four materials, different from each other by structure and surface texture, and applied methods of fractal geometry to investigate their microstructure and roughening mechanism at different thickness values. Our findings show that the film growth does not follow any known class of universality, but is strongly influenced by non-local effects inherent to deposition technique. In this context, we show that deposition onto rough materials is dominated by a strong memory effect that leads to uniform surface coverages that microscopically retain the shape of the substrate. This circumstance is potentially useful for deposition of conformal coatings in view of applications of such plasma-based deposition technique to cases of technological interest.

2018 - A review on ionic substitutions in hydroxyapatite thin films: Towards complete biomimetism [Articolo su rivista]
Graziani, G.; Boi, M.; Bianchi, M.
abstract

Plasma sprayed coatings composed of stoichiometric hydroxyapatite have been extensively used to improve integration of metallic implants in the host bone, as hydroxyapatite (HA) is normally regarded as similar to the mineralized phase of bone. However, these coatings exhibited several drawbacks that limited their success. On the one hand biological apatite is a carbonated-HA, containing significant amounts of foreign ions, having low crystallinity and a small crystals size. This means that it differs from stoichiometric HA in terms of composition, stoichiometry, crystallinity degree, crystal size/morphology and, as a direct consequence, solubility, and ions release in the peri-implant environment. On the other hand, thick plasma sprayed coatings can undergo cracking and delamination and are scarcely uniform. For these reasons, research is pushing into two directions: (i) Increasing the similarity of apatite coatings to real bone, and (ii) exploring deposition by alternative plasma assisted techniques, allowing to achieve thin films, and having superior adhesion and a better control over the coating composition. In this article, we review the latest advances in the field of plasma-assisted deposition of ion-substituted hydroxyapatite thin films, highlighting the state of the art, the limitations, potentialities, open challenges, and the future scenarios for their application.

2018 - Bone regeneration in a rabbit critical femoral defect by means of magnetic hydroxyapatite macroporous scaffolds [Articolo su rivista]
Russo, A; Bianchi, M.; Sartori, M; Boi, M; Giavaresi, G; Salter D., M; Jelic, M; Maltarello M., C; Ortolani, A; Sprio, S; Fini, M; Tampieri, A
abstract

Magnetic scaffolds have recently attracted significant attention in tissue engineering due to the prospect of improving bone tissue formation by conveying soluble factors such as growth factors, hormones, and polypeptides directly to the site of implantation, as well as to the possibility of improving implant fixation and stability. The objective of this study was to compare bone tissue formation in a preclinical rabbit model of critical femoral defect treated either with a hydroxyapatite (HA)/magnetite (90/10 wt %) or pure HA porous scaffolds at 4 and 12 weeks after implantation. The biocompatibility and osteogenic activity of the novel magnetic constructs was assessed with analysis of the amount of newly formed bone tissue and its nanomechanical properties. The osteoconductive properties of the pure HA were confirmed. The HA/magnetite scaffold was able to induce and support bone tissue formation at both experimental time points without adverse tissue reactions. Biomechanically, similar properties were obtained from nanoindentation analysis of bone formed following implantation of magnetic and control scaffolds. The results indicate that the osteoconductive properties of an HA scaffold are maintained following inclusion of a magnetic component. These provide a basis for future studies investigating the potential benefit in tissue engineering of applying magnetic stimuli to enhance bone formation. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 546-554, 2018.

2018 - Structural and ultrastructural analyses of bone regeneration in rabbit cranial osteotomy: Piezosurgery versus traditional osteotomes. [Articolo su rivista]
Anesi, Alexandre; Ferretti, Marzia; Cavani, Francesco; Salvatori, Roberta; Bianchi, Michele; Alessandro, Russo; Chiarini, Luigi; Palumbo, Carla; Bianchi, Michele
abstract

Clinical advantages of piezosurgery have been already proved. However, few investigations have focused on the dynamics of bone healing. The aim of this study was to evaluate, in adult rabbits, bone regeneration after cranial linear osteotomies with two piezoelectrical devices (Piezosurgery® Medical - PM and Piezosurgery® Plus - PP), comparing them with conventional rotary osteotomes (RO). PP was characterized by an output power three times higher than PM. Fifteen days after surgery, histomorphometric analyses showed that the osteotomy gap produced with PM and PP was about half the size of that produced by RO, and in a more advanced stage of recovery. Values of regenerated bone area with respect to the total osteotomy area were about double in PM and PP samples compared with RO ones, while the number of TRAP-positive (tartrate-resistant acid phosphatase positive) osteoclasts per linear surface showed a significant increase, suggesting greater bone remodelling. Under scanning electron microscopy, regenerated bone displayed higher cell density and less mineralized matrix compared with pre-existent bone for all devices used. Nanoindentation tests showed no changes in elastic modulus. In conclusion, PM/PP osteotomies can be considered equivalent to each other, and result in more rapid healing compared with those using RO.

2017 - A Nanomechanical Investigation of Engineered Bone Tissue Comparing Elastoplastic and Viscoelastoplastic Modeling [Articolo su rivista]
Boi, Marco; Marchiori, Gregorio; Sartori, Maria; Salamanna, Francesca; Graziani, Gabriela; Russo, Alessandro; Visani, Andrea; Girolami, Mauro; Fini, Milena; Bianchi, Michele
abstract

It is common practice to implement the elastoplastic Oliver and Pharr (OP) model to investigate the spatial and temporal variations of mechanical properties of engineered bone. However, the viscoelastoplastic (VEP) model may be preferred being envisaged to provide additional insights into the regeneration process, as it allows evaluating also the viscous content of bone tissue. In this work, the elastic modulus (ER), contact hardness (HC), hardness (H), and viscosity index (ηQ) of newly formed bone tissue regenerated at 4 and 12 weeks from the implantation of a macroporous hydroxyapatite scaffold in a rabbit femoral critical-size model were addressed and compared to the mechanical properties of preexisting bone. Indentation curves were fitted with both the OP and VEP models. The VEP model outlined a wider gap between the mechanical properties of native and regenerated tissue when compared to the OP model. In addition, the VEP model indicated an increase of the viscosity index from 4 to 12 weeks, supporting the evidence of a still active regeneration process. The reported results confirmed the higher ability of VEP model compared to the more diffused OP model to provide important insights into bone mechanical properties, also during the bone regeneration process.

2017 - Corrigendum to: Osteogenic differentiation of hDPSCs on biogenic bone apatite thin films (Stem Cells International (2017) 2017 (3579283) DOI: 10.1155/2017/3579283) [Articolo su rivista]
Bianchi, Michele; Pisciotta, Alessandra; Bertoni, Laura; Berni, Matteo; Gambardella, Alessandro; Visani, Andrea; Russo, Alessandro; DE POL, Anto; Carnevale, Gianluca
abstract

In the article titled "Osteogenic differentiation of hDPSCs on biogenic bone apatite thin films" [1], the second affiliation was incorrect. The corrected affiliations are shown above.

2017 - Effects of working gas pressure on zirconium dioxide thin film prepared by pulsed plasma deposition: roughness, wettability, friction and wear characteristics [Articolo su rivista]
Bernia, M.; Marchiori, G.; Gambardella, A.; Boi, M.; Bianchi, M.; Russo, A.; Visani, A.; Marcaccia, M.; Pavan, P. G.; Lopomo, N. F.
abstract

In joint arthroplasty one of the main issues related to the failure of prosthetic implants is due to the wear of the ultra-high molecular weight polyethylene (UHMWPE) component. Surface treatments and coatings have been recognized as enhancing methods, able to improve the tribological properties of the implants. Therefore, the main objective of this work was to investigate the possibility to fabricate yttria-stabilized zirconia (YSZ) coatings on a metal (AISI 316-L) substrate by means of Pulsed Electron Deposition, in order to improve the tribological behavior of the polymer-metal coupling, by reducing the initial wear of the UHMWPE component. In order to optimize the coating characteristics, the effects of working gas pressure on both its morphological and tribological properties were analyzed. Morphological characterization of the films was evaluated by Atomic Force Microscopy (AFM). Coating wettability was also estimated by contact angle (CA) measurement. Tribological performance (coupling friction and wear of UHMWPE) was evaluated by using a ball-on-disc tribometer during highly-stressing tests in dry and lubricated (i.e. NaCl and serum) conditions; friction and wear were specifically evaluated at the initial sliding distances - to highlight the main effect of coating morphology - and after 100 m - where the influence of the intrinsic materials properties prevails. AFM analysis highlighted that the working pressure heavily affected the morphological characteristics of the realized films. The wettability of the coating at the highest and lowest deposition pressures (CA ~ 60°, closed to substrate value) decreased for intermediate pressures, reaching a maximum CA of ~ 90°. Regarding tribological tests, a strong correlation was found in the initial steps between friction coefficient and wettability, which decreased as the distance increased. Concerning UHMWPE wear associated to coated counterpart, at 100 m a reduction rate of about 7% in dry, 12% in NaCl and 5% in presence of serum was obtained compared to the uncoated counterpart. Differently from what highlighted for friction, no correlation was found between wear rate and morphological parameters. These findings, in agreement with literature, underlined the effect of the deposition pressure on the morphological properties, but suggested that physical characteristics are influenced too. Further research on the deposition process will be required in order to improve the tribological performance of the coating at long distances, addressing – above all - orthopedic applications.

2017 - Interfacing Polymers and Tissues: Quantitative Local Assessment of the Foreign Body Reaction of Mononuclear Phagocytes to Polymeric Materials [Articolo su rivista]
Giusto, Elena; Donegà, Matteo; Dumitru, Andra C.; Foschi, Giulia; Casalini, Stefano; Bianchi, Michele; Leonardi, Tommaso; Russo, Alessandro; Occhipinti, Luigi G.; Biscarini, Fabio; Garcia, Ricardo; Pluchino, Stefano
abstract

A quantitative method to assess the in vitro foreign body reaction (FBR) of mononuclear phagocytes (MP) to polymers relevant in implants for prosthetics, advanced therapies, and regenerative medicine is presented. It integrates single-cell force spectroscopy (SCFS) with immunogenic profiles of the MPs. In cell force spectroscopy experiments a single phagocyte, linked at the end of an atomic force microscopy cantilever, probes the adhesion forces between the cell and the polymer surface. SCFS measures adhesion forces in a range from 10 pN to 100 nN and with spatial resolution from cell size down to nanometers, accessing the early adhesion events established at contact times between milliseconds and minutes. The time evolution within the first 60 s of the adhesion force between the phagocyte and the polymer surface before and after the treatment with an immunosuppressive drug, viz. Minocycline, a Federal Drug Administration (FDA)-approved third generation tetracycline with anti-inflammatory effects, is then studied. The adhesion force values measured at the single cell level is shown to correlate to the immunogenic profiles obtained by analysis of biomarkers and morphology of the MPs in culture. Also, Minocycline causes a decrease of both proinflammatory gene expression profiles and adhesive forces of single cells.

2017 - Ion-substituted calcium phosphate coatings deposited by plasma-assisted techniques: A review [Articolo su rivista]
Graziani, Gabriela; Bianchi, Michele; Sassoni, Enrico; Russo, Alessandro; Marcacci, Maurilio
abstract

One of the main critical aspects behind the failure or success of an implant resides in its ability to fast bond with the surrounding bone. To boost osseointegration, the ideal implant material should exhibit composition and structure similar to those of biological apatite. To this aim, the most common approach is to coat the implant surface with a coating of hydroxyapatite (HA), resembling the main component of mineralized tissues. However, bone apatite is a non-stoichiometric, multi-substituted poorly-crystalline apatite, containing significant amounts of foreign ions, with high biological relevance. Ion-substituted HAs can be deposited by so called “wet methods”, which are however poorly reproducible and hardly industrially feasible; at the same time bioactive coatings realized by plasma assisted method, interesting for industrial applications, are generally made of stoichiometric (i.e. un-substituted) HA. In this work, the literature concerning plasma-assisted deposition methods used to deposit ion-substituted HA was reviewed and the last advances in this field discussed. The ions taken into exam are those present in mineralized tissues and possibly having biological relevance. Notably, literature about this topic is scarce, especially relating to in vivo animal and clinical trials; further on, available studies evaluate the performance of substituted coatings from different points of view (mechanical properties, bone growth, coating dissolution, etc.) which hinders a proper evaluation of the real efficacy of ion-doped HA in promoting bone regeneration, compared to stoichiometric HA. Moreover, results obtained for plasma sprayed coatings (which is the only method currently employed for deposition at the industrial scale) were collected and compared to those of novel plasma-assisted techniques, that are expected to overcome its limitations. Data so far available on the topic were discussed to highlight advantages, limitations and possible perspectives of these procedures.

2017 - Osteogenic Differentiation of hDPSCs on Biogenic Bone Apatite Thin Films [Articolo su rivista]
Bianchi, Michele; Pisciotta, Alessandra; Bertoni, Laura; Berni, Matteo; Gambardella, Alessandro; Visani, Andrea; Russo, Alessandro; DE POL, Anto; Carnevale, Gianluca
abstract

A previous study reported the structural characterization of biogenic apatite (BAp) thin films realized by a pulsed electron deposition system by ablation of deproteinized bovine bone. Thin films annealed at 400 degrees C exhibited composition and crystallinity degree very close to those of biogenic apatite; this affinity is crucial for obtaining faster osseointegration compared to conventional, thick hydroxyapatite (HA) coatings, for both orthopedics and dentistry. Here, we investigated the adhesion, proliferation, and osteogenic differentiation of human dental pulp stem cells (hDPCS) on as-deposited and heat-treated BAp and stoichiometric HA. First, we showed that heat-treated BAp films can significantly promote hDPSC adhesion and proliferation. Moreover, hDPSCs, while initially maintaining the typical fibroblast-like morphology and stemness surface markers, later started expressing osteogenic markers such as Runx-2 and OSX. Noteworthy, when cultured in an osteogenic medium on annealed BAp films, hDPSCs were also able to reach a more mature and terminal commitment, with respect to HA and as-deposited films. Our findings suggest that annealed BAp films not only preserve the typical biological properties of stemness of, hDPSCs but also improve their ability of osteogenic commitment.

2017 - Plasma-assisted deposition of bone apatite-like thin films from natural apatite [Articolo su rivista]
Bianchi, Michele; Gambardella, Alessandro; Graziani, Gabriela; Liscio, Fabiola; Cristina Maltarello, Maria; Boi, Marco; Berni, Matteo; Bellucci, Devis; Marchiori, Gregorio; Valle, Francesco; Russo, Alessandro; Marcacci, Maurilio
abstract

In orthopedics and dentistry, novel approaches for fabricating biomimetic and mechanically robust bioactive coatings are highly desirable in order to truly improve the clinical results of coated implants compared to uncoated ones. In this paper, a biological-like apatite coating is deposited for the first time by plasma-assisted deposition of a natural apatite source. Specifically, we deposited bone apatite-like (BAL) thin films from bone apatite targets by pulsed electron deposition (PED). Morphology, composition, structure and mechanical properties of as-deposited and annealed BAL and stoichiometric hydroxyapatite (HA) films were investigated. While as-deposited BAL and HA films were poorly crystalline at room temperature, they crystallized to an extent very close to that of natural apatite when annealed at 400 °C. In addition, FTIR analysis pointed out that BAL films closely resembled the composition of the starting natural apatite target. Finally, nanoindentation tests indicated that BAL films with high mechanical properties could be deposited by PED.

2017 - Pulsed Electron Deposition of nanostructured bioactive glass coatings for biomedical applications [Articolo su rivista]
Bellucci, Devis; Bianchi, Michele; Graziani, Gabriela; Gambardella, Alessandro; Berni, Matteo; Russo, Alessandro; Cannillo, Valeria
abstract

Due to poor mechanical properties and brittleness of bioactive glasses, the deposition of bioactive glass coatings on bioinert metallic implants for bone regeneration is a promising route to combine the high bioactivity of the glassy phase with the mechanical strength of metallic substrate. The Pulsed Electron Deposition (PED) technique has been recently demonstrated to be an effective method to fabricate highly-adherent and nanostructured bioactive thin films and coatings, with fine control over film composition. In this paper, we investigated the deposition by PED of 45S5 Bioglass® and of a novel CaO-rich bioactive glass, also containing potassium oxide. Composition, microstructure, surface morphology, wettability and adhesion to the titanium substrate were assessed for both as-deposited and annealed coatings. All samples exhibited a nanostructured surface morphology and high hydrophilicity, both positive features for biological applications. In particular, annealed samples exhibited increased roughness and adhesion degree to the titanium substrate compared to the as-deposited ones. The results showed in this paper suggest that bioactive glass coatings deposited by PED are promising for being further investigated as bioactive coatings for bone implants.

2017 - Strontium doped calcium phosphate coatings on poly(etheretherketone) (PEEK) by pulsed electron deposition [Articolo su rivista]
Bianchi, Michele; Degli Esposti, Lorenzo; Ballardini, Alberto; Liscio, Fabiola; Berni, Matteo; Gambardella, Alessandro; Leeuwenburgh, Sander C. G.; Sprio, Simone; Ampieri, Annat; Lafisco, Michele
abstract

Herein the preparation of Sr2 +-doped calcium phosphate (CaP) coatings on poly(etheretherketone) (PEEK) substrates by pulsed electron deposition (PED) was investigated. Hydroxyapatites (HA) substituted with tailored amounts of Sr2 + up to 9 wt% were synthesized to generate the deposition targets. Dense and uniform amorphous CaP films having Sr/Ca molar ratios close to that of targets were achieved. The roughness and the wettability of the bare PEEK were significantly enhanced after coating deposition. The presence of Sr2 + led to a slight increase of the particles size while it did not mainly affect the RMS of the coatings that consisted of nanostructured aggregates of globular shape. After a mild annealing treatment at 130 °C for 6 h, the amorphous coatings transformed into nanocrystalline HA films incorporating Sr2 + having Sr/Ca molar ratios close to those of the as-deposited films. The annealing did not affect the topography and the roughness of the coatings, while improved the hardness of the films un-doped and doped at low-extent. This study shows that PED is feasible technique to coat PEEK implants with CaP films with control over the Sr/Ca ratio, which could improve bone fixation and in vivo stability especially under osteoporotic conditions thanks to the anabolic effect of Sr2 +.

2016 - Ceramic coatings for orthopaedic implants: preparation and characterization [Articolo su rivista]
Kaciulis, S.; Mezzi, A.; Bianchi, M.; Gambardella, A.; Boi, M.; Liscio, F.; Marcacci, M.; Russo, A.
abstract

Ceramic coatings are increasingly used for orthopaedic implants to improve the wear resistance and to enhance the integration into bone tissue, resulting in the long-term stability of the implant. The innovative pulsed plasma deposition technique was used to deposit at room temperature different thin films with required mechanical parameters and good adhesion to the substrate. In this way, the films of nanostructured hydroxyapatite, magnetic hydroxyapatite, zirconia and zirconia - alumina were produced and investigated by X-ray diffraction, atomic force microscopy and XPS depth profiling techniques. Obtained results revealed the good stoichiometry, sufficient purity of chemical composition, very high uniformity in depth and thermal stability in ultra-high vacuum of all investigated coatings. Copyright © 2015 John Wiley & Sons, Ltd.

2016 - Magnetic forces and magnetized biomaterials provide dynamic flux information during bone regeneration [Articolo su rivista]
Russo, Alessandro; Bianchi, Michele; Sartori, Maria; Parrilli, Annapaola; Panseri, Silvia; Ortolani, Alessandro; Sandri, Monica; Boi, Marco; Salter, Donald M.; Cristina Maltarello, Maria; Giavaresi, Gianluca; Fini, Milena; Dediu, Valentin; Tampieri, Anna; Marcacci, Maurilio
abstract

The fascinating prospect to direct tissue regeneration by magnetic activation has been recently explored. In this study we investigate the possibility to boost bone regeneration in an experimental defect in rabbit femoral condyle by combining static magnetic fields and magnetic biomaterials. NdFeB permanent magnets are implanted close to biomimetic collagen/hydroxyapatite resorbable scaffolds magnetized according to two different protocols. Permanent magnet only or non-magnetic scaffolds are used as controls. Bone tissue regeneration is evaluated at 12 weeks from surgery from a histological, histomorphometric and biomechanical point of view. The reorganization of the magnetized collagen fibers under the effect of the static magnetic field generated by the permanent magnet produces a highly-peculiar bone pattern, with highly-interconnected trabeculae orthogonally oriented with respect to the magnetic field lines. In contrast, only partial defect healing is achieved within the control groups. We ascribe the peculiar bone regeneration to the transfer of micro-environmental information, mediated by collagen fibrils magnetized by magnetic nanoparticles, under the effect of the static magnetic field. These results open new perspectives on the possibility to improve implant fixation and control the morphology and maturity of regenerated bone providing “in site” forces by synergically combining static magnetic fields and biomaterials.

2016 - Magnetic hydroxyapatite coatings as a new tool in medicine: A scanning probe investigation [Articolo su rivista]
Gambardella, A.; Bianchi, M.; Kaciulis, S.; Mezzi, A.; Brucale, M.; Cavallini, M.; Herrmannsdoerfer, T.; Chanda, G.; Uhlarz, M.; Cellini, A.; Pedna, M. F.; Sambri, V.; Marcaccia, M.; Russo, A.
abstract

Hydroxyapatite films enriched with magnetite have been fabricated via a Pulsed Plasma Deposition (PPD) system with the final aim of representing a new platform able to disincentivate bacterial adhesion and biofilm formation. The chemical composition and magnetic properties of films were respectively examined by X-ray photoelectron spectroscopy (XPS) and Superconducting Quantum Interference Device (SQUID) measurements. The morphology and conductive properties of the magnetic films were investigated via a combination of scanning probe technologies including atomic force microscopy (AFM), electrostatic force microscopy (EFM), and scanning tunneling microscopy (STM). Interestingly, the range of adopted techniques allowed determining the preservation of the chemical composition and magnetic properties of the deposition target material while STM analysis provided new insights on the presence of surface inhomogeneities, revealing the presence of magnetite-rich islands over length scales compatible with the applications. Finally, preliminary results of bacterial adhesion tests, indicated a higher ability of magnetic hydroxyapatite films to reduce Escherichia coli adhesion at 4 h from seeding compared to control hydroxyapatite films.

2016 - Optimizing thickness of ceramic coatings on plastic components for orthopedic applications: A finite element analysis [Articolo su rivista]
Marchiori, G.; Lopomo, N.; Boi, M.; Berni, M.; Bianchi, M.; Gambardella, A.; Visani, A.; Russo, A.; Marcacci, M.
abstract

Realizing hard ceramic coatings on the plastic component of a joint prosthesis can be strategic for the mechanical preservation of the whole implant and to extend its lifetime. Recently, thanks to the Plasma Pulsed Deposition (PPD) method, zirconia coatings on ultra-high molecular weight polyethylene (UHMWPE) substrates resulted in a feasible outcome. Focusing on both the highly specific requirements defined by the biomedical application and the effective possibilities given by the deposition method in the perspectives of technological transfer, it is mandatory to optimize the coating in terms of load bearing capacity. The main goal of this study was to identify through Finite Element Analysis (FEA) the optimal coating thickness that would be able to minimize UHMWPE strain, possible insurgence of cracks within the coating and stresses at coating-substrate interface. Simulations of nanoindentation and microindentation tests were specifically carried out. FEA findings demonstrated that, in general, thickening the zirconia coating strongly reduced the strains in the UHMWPE substrate, although the 1 μm thickness value was identified as critical for the presence of high stresses within the coating and at the interface with the substrate. Therefore, the optimal thickness resulted to be highly dependent on the specific loading condition and final applications.

2016 - Surface morphology, tribological properties and in vitro biocompatibility of nanostructured zirconia thin films [Articolo su rivista]
Bianchi, M.; Gambardella, A.; Berni, M.; Panseri, S.; Montesi, M.; Lopomo, N.; Tampieri, A.; Marcacci, M.; Russo, A.
abstract

Deposition of nanostructured and low-wear zirconia (ZrO2) thin films on the metallic component of a total joint implant is envisaged to reduce wear of the soft ultra-high molecular weight polyethylene (UHMWPE) counterpart. In this work, morphological surface features, wear resistance and in vitro-biocompatibility of zirconia thin films deposited by the novel Pulsed Plasma Deposition (PPD) method have been investigated. Film thickness, roughness and wettability were found to be strongly dependent on deposition gas pressure. Interestingly, wear rate of UHMWPE disks coupled to zirconia-coated titanium spheres was only poorly correlated to the contact angle values, while film roughness and thickness seemed not to affect it. Furthermore, wear of UHMWPE, when coupled with zirconia coated-titanium spheres, significantly decreased with respect to uncoated spheres under dry or NaCl-lubricated conditions; besides, when using bovine serum, similar results were obtained for coated and uncoated spheres. Finally, suitable mesenchymal stem and osteoblast cells adhesion, proliferation and viability were observed, suggesting good biocompatibility of the nanostructured zirconia films. Taken together, the results shown in this work indicate that zirconia thin films deposited by the PPD method deserve further investigations as low-wear materials for biomedical applications such as total joint replacement.

2016 - The prospective opportunities offered by magnetic scaffolds for bone tissue engineering: A review [Articolo su rivista]
Ortolani, Alessandro; Bianchi, Michele; Mosca, Massimiliano; Caravelli, Silvio; Fuiano, Mario; Marcacci, Maurilio; Russo, Alessandro
abstract

Magnetic scaffolds are becoming increasingly attractive in tissue engineering, due to their ability to enhance bone tissue formation by attracting soluble factors, such as growth factors, hormones and polypeptides, directly to the implantation site, as well as their potential to improve the fixation and stability of the implant. Moreover, there is increasing evidence that the synergistic effects of magnetic scaffolds and magnetic fields can promote bone repair and regeneration. in this manuscript we review the recent innovations in bone tissue engineering that exploit magnetic biomaterials combined with static magnetic fields to enhance bone cell adhesion and proliferation, and thus bone tissue growth.

2016 - Tribological characterization of zirconia coatings deposited on Ti6Al4V components for orthopedic applications [Articolo su rivista]
Berni, M.; Lopomo, N.; Marchiori, G.; Gambardella, A.; Boi, M.; Bianchi, M.; Visani, A.; Pavan, P.; Russo, A.; Marcacci, M.
abstract

One of the most important issues leading to the failure of total joint arthroplasty is related to the wear of the plastic components, which are generally made of ultra high molecular weight polyethylene (UHMWPE). Therefore, the reduction of joint wear represents one of the main challenges the research in orthopedics is called to address nowadays. Surface treatments and coatings have been recognized as innovative methods to improve tribological properties, also in the orthopedic field. This work investigated the possibility to realize hard ceramic coatings on the metal component of a prosthesis, by means of Pulsed Plasma Deposition, in order to reduce friction and wear in the standard coupling against UHMWPE. Ti6Al4V substrates were coated with a 2 μm thick yttria-stabilized zirconia (YSZ) layer. The mechanical properties of the YSZ coatings were assessed by nanoindentation tests performed on flat Ti6Al4V substrates. Tribological performance was evaluated using a ball-on-disk tribometer in dry and lubricated (i.e. with fetal bovine serum) highly-stressing conditions, up to an overall distance of 10 km. Tribology was characterized in terms of coefficient of friction (CoF) and wear rate of the UHMWPE disk. After testing, specimens were analyzed through optical microscopy and SEM images, in order to check the wear degradation mechanisms. Progressive loading scratch tests were also performed in dry and wet conditions to determine the effects of the environment on the adhesion of the coating. Our results supported the beneficial effect of YSZ coating on metal components. In particular, the proposed solution significantly reduced UHMWPE wear rate and friction. At 10 km of sliding distance, a wear rate reduction of about 18% in dry configuration and of 4% in presence of serum, was obtained by the coated group compared to the uncoated group. As far as friction in dry condition is concerned, the coating allowed to maintain low CoF values until the end of the tests, with an overall difference of about 40% compared to the uncoated balls. In wet conditions, the friction values were found to be comparable between coated and uncoated materials, mainly due to a premature delamination of the coating. Scratch tests in wet showed in fact a reduction of the critical load required to a complete delamination due to a formation of blister, although no change or damage occurred at the coating during the soaking period. Although conditions of high values of contact pressure were considered, further analyses are however required to fully understand the behavior of YSZ coatings in wet environment and additional research on the deposition process will be mandatory in order to improve the coating tribological performance at long distances addressing orthopedic applications.

2015 - Ceramic thin films realized by means of pulsed plasma deposition technique: Applications for orthopedics [Articolo su rivista]
Bianchi, Michele; Lopomo, Nicola; Boi, Marco; Gambardella, Alessandro; Marchiori, Gregorio; Berni, Matteo; Pavan, Piero; Marcacci, Maurilio; Russo, Alessandro
abstract

Joint prosthesis are usually subjected to several failing mechanisms, including wear of the ultra-high molecular weight polyethylene (UHMWPE) insert. The main goal of this study was to assess the possibility to improve the tribological properties of titanium component by depositing zirconia thin films on its surface by pulsed plasma deposition (PPD) method. Zirconiacoated titanium spheres were tested against UHMWPE disks, both in dry and wet conditions. Zirconia films exhibited a homogenous sub-micrometric grain size distribution and low roughness. Interestingly, zirconia-coated titanium spheres showed lower wear rate of the UHMWPE component, compared to uncoated titanium spheres, supporting the feasibility of the proposed approach.

2015 - NANOMECHANICAL CHARACTERIZATION OF ZIRCONIA THIN FILMS DEPOSITED ON UHMWPE BY PULSED PLASMA DEPOSITION [Articolo su rivista]
Bianchi, Michele; Boi, Marco; Lopomo, Nicola; CRISTINA MALTARELLO, Maria; Liscio, Fabiola; Milita, Silvia; Visani, Andrea; Russo, Alessandro; Marcacci, Maurilio
abstract

2015 - Nanomechanical mapping of bone tissue regenerated by magnetic scaffolds [Articolo su rivista]
Bianchi, Michele; Boi, Marco; Sartori, Maria; Giavaresi, Gianluca; Lopomo, Nicola; Fini, Milena; Dediu, Alek; Tampieri, Anna; Marcacci &, Maurilio; Russo, Alessandro
abstract

Nanoindentation can provide new insights on the maturity stage of regenerating bone. The aim of the present study was the evaluation of the nanomechanical properties of newly-formed bone tissue at 4 weeks from the implantation of permanent magnets and magnetic scaffolds in the trabecular bone of rabbit femoral condyles. Three different groups have been investigated: MAG-A (NdFeB magnet + apatite/collagen scaffold with magnetic nanoparticles directly nucleated on the collagen fibers during scaffold synthesis); MAG-B (NdFeB magnet + apatite/collagen scaffold later infiltrated with magnetic nanoparticles) and MAG (NdFeB magnet). The mechanical properties of different-maturity bone tissues, i.e. newly-formed immature, newly-formed mature and native trabecular bone have been evaluated for the three groups. Contingent correlations between elastic modulus and hardness of immature, mature and native bone have been examined and discussed, as well as the efficacy of the adopted regeneration method in terms of "mechanical gap" between newly-formed and native bone tissue. The results showed that MAG-B group provided regenerated bone tissue with mechanical properties closer to that of native bone compared to MAG-A or MAG groups after 4 weeks from implantation. Further, whereas the mechanical properties of newly-formed immature and mature bone were found to be fairly good correlated, no correlation was detected between immature or mature bone and native bone. The reported results evidence the efficacy of nanoindentation tests for the investigation of the maturity of newly-formed bone not accessible through conventional analyses.

2015 - Tough and adhesive nanostructured calcium phosphate thin films deposited by the pulsed plasma deposition method [Articolo su rivista]
Boi, Marco; Bianchi, Michele; Gambardella, Alessandro; Liscio, Fabiola; Kaciulis, Saulius; Visani, Andrea; Barbalinardo, Marianna; Valle, Francesco; Iafisco, Michele; Lungaro, Lisa; Milita, Silvia; Cavallini, Massimiliano; Marcacci, Maurilio; Russo, Alessandro
abstract

2014 - Multifunctional ceramic thin films for high-performance orthopaedic implants [Relazione in Atti di Convegno]
Bianchi, M; Lopomo N; Boi M; Maltarello, M. C. ; Liscio F. ; Marcacci M.; Russo, A.
abstract

Protective hard films on soft inorganic/organic substrates are appealing for several technological applications like solar cells, organic electronics, fuel cells, etc. The main concern is still related to the bad quality of the interface and to the weak mechanical properties of the film as a consequence of the low working temperatures mandatory to prevent substrate softening/melting. Our research activity at Rizzoli Orthopaedic Institute is mainly directed toward the deposition of functional ceramic thin films to improve the mechanical properties (and thus the clinical performances) of the load-bearing plastic component of the prosthetic implant. To this aim, we use a novel sputter-based electron deposition technique named Pulsed Plasma Deposition (PPD) able to provide nanostructured ceramic thin films highly adhered to the plastic substrate and with optimum mechanical performances even if working at room temperature and using very-soft substrates.

2014 - Neural cell alignment by patterning gradients of the extracellular matrix protein laminin [Articolo su rivista]
Chelli, Beatrice; Barbalinardo, Marianna; Valle, Francesco; Greco, Pierpaolo; Bystrenova, Eva; Bianchi, Michele; Biscarini, Fabio
abstract

Anisotropic orientation and accurate positioning of neural cells is achieved by patterning stripes of the extracellular matrix protein laminin on the surface of polystyrene tissue culture dishes by micromoulding in capillaries (MIMICs). Laminin concentration decreases from the entrance of the channels in contact with the reservoir towards the end. Immunofluorescence analysis of laminin shows a decreasing gradient of concentration along the longitudinal direction of the stripes. The explanation is the superposition of diffusion and convection of the solute, the former dominating at length scales near the entrance (characteristic length around 50 μm), the latter further away (length scale in excess of 900 μm). These length scales are independent of the channel width explored from about 15 to 45 μm. Neural cells are randomly seeded and selectively adhere to the pattern, leaving the unpatterned areas depleted even upon 6 days of incubation. Cell alignment was assessed by the orientation of the long axis of the 4',6-diamidino-2-phenylindole-stained nuclei. Samples on patterned the laminin area exhibit a large orientational order parameter. As control, cells on the unpatterned laminin film exhibit no preferential orientation. This implies that the anisotropy of laminin stripes is an effective chemical stimulus for cell recruiting and alignment.

2014 - Substrate geometry directs the in vitro mineralization of calcium phosphate ceramics [Articolo su rivista]
Bianchi, Michele; Urquia Edreira, Eva R.; Wolke, Joop G. C.; Birgani, Zeinab T.; Habibovic, Pamela; Jansen, John A.; Tampieri, Anna; Marcacci, Maurilio; Leeuwenburgh, Sander C. G.; van den Beucken, Jeroen J. J. P.
abstract

Repetitive concavities on the surface of bone implants have recently been demonstrated to foster bone formation when implanted at ectopic locations in vivo. The current study aimed to evaluate the effect of surface concavities on the surface mineralization of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) ceramics in vitro. Hemispherical concavities with different diameters were prepared at the surface of HA and β-TCP sintered disks: 1.8 mm (large concavity), 0.8 mm (medium concavity) and 0.4 mm (small concavity). HA and β-TCP disks were sintered at 1100 or 1200 °C and soaked in simulated body fluid for 28 days at 37 °C; the mineralization process was followed by scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction and calcium quantification analyses. The results showed that massive mineralization occurred exclusively at the surface of HA disks treated at 1200 °C and that nucleation of large aggregates of calcium phosphate started specifically inside small concavities instead of on the planar surface of the disks. Regarding the effect of concavity diameter size on surface mineralization, it was observed that small concavities induce 124- and 10-fold increased mineralization compared to concavities of large or medium size, respectively. The results of this study demonstrated that (i) in vitro surface mineralization of calcium phosphate ceramics with surface concavities starts preferentially within the concavities and not on the planar surface, and (ii) concavity size is an effective parameter to control the spatial position and extent of mineralization in vitro. © 2013 Acta Materialia Inc.

2013 - Pulsed plasma deposition of zirconia thin films on UHMWPE: Proof of concept of a novel approach for joint prosthetic implants [Articolo su rivista]
Bianchi, Michele; Russo, Alessandro; Lopomo, Nicola; Boi, Marco; Cristina Maltarello, Maria; Sprio, Simone; Baracchi, Matteo; Marcacci, Maurilio
abstract

Wear of ultra-high molecular weight polyethylene (UHMWPE) has been recognized as the main cause for long-term revision in joint arthroplasty. A new approach to overcome this detrimental issue is here presented: zirconia (ZrO2) thin films were directly deposited onto the surface of UHMWPE by Pulsed Plasma Deposition (PPD) technique. The obtained films were structurally, morphologically and mechanically characterized by X-ray diffraction, scanning electron microscopy and nanoindentation tests, respectively. The critical fracture load was estimated by the analysis of the indenter footprints, while the adhesion degree was evaluated by a cross-cut tape test. Zirconia films exhibited a fully cubic structure, with densely packed grains, whereas mechanical tests showed that hard, tough and well-adherent films were deposited. These preliminary results suggested the feasibility of pursuing this alternative route to improve UHMPWE performances while preserving its well-established mechanical properties. © 2013 The Royal Society of Chemistry.

2012 - Cell-fluidics: producing cellular streams on micropatterned synthetic surfaces [Articolo su rivista]
M., Ventre; F., Valle; M., Bianchi; Biscarini, Fabio; P., Netti
abstract

Patterning cell-adhesive molecules on material surfaces provides a powerful tool for controlling and guiding cell locomotion and migration. Here we report fast, reliable, easy to implement methods to fabricate large patterns of proteins on synthetic substrates to control the direction and speed of cells. Two common materials exhibiting very different protein adsorption capacities, namely, polystyrene and Teflon, were functionalized with micrometric stripes of laminin. The protein was noncovalently immobilized onto the surface by following either lithographically controlled wetting (LCW) or micromolding in capillaries (MIMIC). These techniques proved to be sufficiently mild so as not to interfere with the protein adhesion capability. Cells adhered onto the functionalized stripes and remained viable for more than 20 h. During this time frame, cells migrated along the lanes and the dynamics of motion was strongly affected by the substrate surface chemistry and culturing conditions. In particular, enhanced mismatches of cell adhesive properties obtained by the juxtaposition of bare and laminin-functionalized Teflon caused cells to move slowly and their movement to be highly confined. The patterning procedure was also effective at guiding migration on conventional cell culture dishes that were functionalized with laminin patterns, even in the presence of serum proteins, although to a lesser extent compared to that for Teflon. This work demonstrates the possibility of creating well-defined, long-range cellular streams on synthetic substrates by pursuing straightforward functionalizing techniques that can be implemented for a broad class of materials under conventional, long-time cell-culturing conditions. The procedure effectively confines cells to migrate along predefined patterns and can be implemented in different biomedical and biotechnological applications.

2012 - Ethanol disinfection affects physical properties and cell response of electrospun poly(l-lactic acid) scaffolds [Articolo su rivista]
Gualandi, C; Govoni, M; Foroni, L; Valente, S; Bianchi, M; Giordano, E; Pasquinelli, F; Biscarini, Fabio; Focarete, Ml
abstract

Disinfection of electrospun materials is commonly carried out by ethanol (EtOH) soaking. However, in the literature no systematic investigation on the effect of EtOH disinfection on scaffold properties is available. In this study electrospun poly(L-lactic acid) (PLLA) scaffolds were differently treated in EtOH and changes of fiber morphology, fiber surface topography and scaffold thermo-mechanical properties were evaluated. It was found that EtOH induced the formation of an amount of crystal phase, in the initially amorphous fibers, which depends on EtOH grade, soaking time and temperature. Completely amorphous PLLA (a-PLLA) and semicrystalline PLIA (sc-PLLA) scaffolds were produced by applying different EtOH treatments to as-spun PLLA scaffold. Compared to a-PLLA, sc-PLLA was stiffer and composed of fibers with rougher surface. Cell culture performed by using permanent cell line H9c2 demonstrated that changes of scaffold properties determined a different cell response, in particular in the expression of proteins correlated to cell motility and cell adhesion.

2012 - Nanotechnology for forensic sciences: Analysis of PDMS replica of the case head of spent cartridges by optical microscopy, SEM and AFM for the ballistic identification of individual characteristic features of firearms [Articolo su rivista]
F., Valle; M., Bianchi; S., Tortorella; G., Pierini; BISCARINI, FABIO; M., D’Elia
abstract

A novel application of replica molding to a forensic problem, viz. the accurate reproduction of the case head of gun and rifle cartridges, prior and after been shot, is presented. The fabrication of an arbitrary number of identical copies of the region hit by the firing pin and by the breech face is described. The replicas can be (i) handled without damaging the original evidence, (ii) distributed to different law enforcement agencies for comparison against other evidences found on crime scenes or ballistic tests of seized firearms, (iii) maintained on a file by the laboratories. A detailed analysis of the morphological features of the replicas has been carried out by standard microscopy techniques as well as by advanced microscopy such as scanning probe and scanning electron leading to a quantitative morphological characterization of the case heads down to the nanometer scale. The assignment of the cartridge replicas to the shooting weapon is demonstrated to hold below the micron scale, while it is hindered at the nanometer level both by the manufacturing differences and by eventual modifications occurring on the firing pin.

2012 - Unconventional Multi-Scale Patterning of Titanium Dioxide: A New Tool for the Investigation of Cell–Topography Interactions [Articolo su rivista]
Biscarini, Fabio; M., Bianchi; B., Chelli; F., Valle; C., Dionigi; E., Bystrenova; P., Greco
abstract

Titanium dioxide (TiO2) is a biocompatible material with important applications in the field of regenerative medicine. Here we show that a multi-scale hierarchical architecture of TiO2, realized with sub-micrometer polystyrene beads as templating agent patterned by micromolding in capillaries (MIMICs), is a viable functional tool for the systematic investigation of cell behavior with respect to a complex topographic texture of the substrate. TiO2 stripes of different width and interconnected porosity whose size ranges from a few hundred to a few tens nanometer, are obtained after thermal treatment of the precursors with concurrent removal of the templating agent. The adhesion and proliferation of two human secondary neural cell lines, i.e., 1321N1 astrocytoma and SH-SY5Y neuroblastoma, on the patterns is statistically assessed with respect to the TiO2 stripe width and porosity. Our results show that cells have a strong preference for TiO2 patterns with respect to glass, the proliferation rate is not affected by cell porosity whereas adhesion is although ligthly, whereas the response of cell density to stripe width is very different in astocytoma cells with respect to neuroblastoma cells.

2011 - One-step substrate nanofabrication and patterning of nanoparticles by lithographically controlled etching [Articolo su rivista]
M., Bianchi; D. L., Herrero; F., Valle; P., Greco P; G. M., Ingo; S., Kalicius; Biscarini, Fabio; M., Cavallini
abstract

We propose an integrated top-down and bottom-up approach to single-step nanofabrication of complex nanostructures made of different materials. The process, termed lithographically controlled etching (LCE), starts with a drop of an etching solution cast on the surface to be patterned. By placing a polymeric mold on the substrate, the stamp protrusions come into contact with the surface, thus protecting it, whereas the surface beneath the mold recesses is exposed to a thin layer of etching solution, allowing the surface to be etched. By dispersing nanoparticles into the etching solution, these can be deposited and self-organize in the recesses on the substrate as these are excavated. We demonstrate here the fabrication of complex structures and nanowires 30 nm wide. Moreover, by exploiting capillary forces, it is possible to deposit nanoparticles at precise positions with respect to optically addressable microstructures, thus realizing a multiscale functional pattern.

2010 - Control of neuronal cell adhesion on single-walled carbon nanotubes 3D patterns [Articolo su rivista]
C., Dionigi; M., Bianchi; O., D’Angelo; A., Shehu; B., Chelli; P., Greco; A., Shehu; I., Tonazzini; A. N., Lazar; Biscarini, Fabio
abstract

2010 - Electrochemiluminescent functionalizable cyclometalated thiophene-based iridium(III) complexes [Articolo su rivista]
Bandini, M.; Bianchi, M.; Valenti, G.; Piccinelli, F.; Paolucci, F.; Monari, M.; Umani-Ronchi, A.; Marcaccio, M.
abstract

2010 - Stable Non-Covalent Large Area Patterning of Inert Teflon-AF Surface: A New Approach to Multiscale Cell Guidance [Articolo su rivista]
F., Valle; B., Chelli; M., Bianchi; P., Greco; E., Bystrenova; I., Tonazzini; Biscarini, Fabio
abstract